1. Field
This disclosure relates generally to improved radio communication, including methods and systems of accurate time-keeping on battery-powered communication devices used in advanced metering infrastructure (AMI) systems, among other environments.
2. Background
Radio communication-based networks are widespread and used for a variety of applications. Such networks are commonly employed in AMI systems that measure, collect, and/or analyze utility usage from electricity, gas, water, and other meters through various communication media. Many AMI systems, particularly those that utilize multi-channel communications, require precise time-keeping on remote communication devices. Generally, the requirement for precise time-keeping has required that devices used in such systems have precise, temperature-compensated crystal oscillators or similar devices, for example, devices having frequency errors as low as 1-2 parts-per-million over a −40 to +85 C operating temperature range. In the case of multi-channel mesh networks, precision is required for hitting frequencies accurately without requiring scanning and searching. More generally, accurate time-keeping at system endpoints (such as meters) facilitates load profiling, consolidated billing, and tamper detection. Unfortunately, precision, temperature-compensated oscillators are comparatively expensive and require more power, making long-term battery operation expensive or altogether non-feasible.